I'm still liking the Fassbender idea, even if no-one else seems to have any thoughts of it, good bad or indifferent!

Here's a link to a fansite with a gallery of pictures. He'd be a slightly offbeat choice for sure and he'd have to bulk up a lot (though 300 showed that he can do that). But if they're looking for someone in the vein of Bale or Craig, an acclaimed and intense actor, rather than a movie star, not to mention someone with a Germanic/ Scandanavian look, I think he'd be a good possibility.